Scope
ISO 11820:2019
In-Situ Sound Attenuation Measurement of Silencers
ISO 11820 specifies the in-situ measurement method for determining the acoustic attenuation performance of silencers installed in railway ventilation ducts, brake systems, and exhaust lines. This test is critical for validating noise control equipment on operating trains and stationary installations where laboratory testing is impractical. Railway manufacturers, maintenance operators, and acoustic engineers use these measurements to verify compliance with noise regulations and to optimize silencer design. Accreditation ensures that attenuation claims are reliable and that performance targets for noise reduction are consistently achieved in real-world applications.
What it measures
- Sound pressure level reduction across silencer (dB)
- Attenuation performance by frequency band
- Insertion loss of silencer in situ
- Acoustic performance under operating conditions
- Noise transmission loss through silencer element
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DIN EN ISO 11821
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BS EN ISO 11821
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NF EN ISO 11821
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UNI EN ISO 11821
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UNE EN ISO 11821
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NEN EN ISO 11821
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DIN EN ISO 3095
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BS EN ISO 3095
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NF EN ISO 3095
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UNI EN ISO 3095
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UNE EN ISO 3095
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NEN EN ISO 3095
1,273
Accredited labs
15
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Showing 826–850 of 1,273 labs
UNE-EN 14363
UNE-EN 50367
UNE-EN 50317
UNE-EN 12663-1
DIN EN ISO 12185
ASTM D 4052
DIN EN ISO 3405
ASTM D 86
DIN EN 13016-1
+ 3 more
PHH Environmental (UK)
Active
HSG 227 (2004))
(HSG 264, 2012)
HSG 264 (2012) and Appx. 3 of
(HSG 248) – 2021
(PCM) based on HSG 248
Parallelendmaße aus 0,5 mm
Einstellringe aus Stahl *
nach DIN EN ISO 3650:1999
Keramik *
DIN EN ISO 3650:1999
+ 3 more
Railway brake — magnetic track brakes (U
− Kraft (WPM)
nur Vor-Ort-Kalibrierungen
Kraft (WPM) 0,1 kN
Vibration measuring instruments — test m
+ 3 more
IEC 60730-1: 2013
DIN EN 60730-2-8
IEC 61000-6-1
DIN EN 50131-2-3
DIN EN 60730-2-9
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rs11887534
HABP2-Gen (c.1601G>A) rs7080536
IEC 61924-2
DIN EN ISO 1974
DIN 53121
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Dosimetrie
Luftkerma
5 mGy
2 mGy
100 µGy
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Paragon Scientific
Active
Refractive Index
Capillary Viscometer Calibration
2.92 mm systems (continued)
Liquids
Density in Air at 20
+ 3 more
Particle Technology
Active
MIL-STD 810D, Method 510.2
MIL-STD 810E, Method 510.3
MIL-STD 810G:2008 Method 501.5
MIL-STD 810F, Method 510.4
MIL-STD-810H, Method 510.7
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Hämoglobin
Selen
Lithium
Zink
Eisen, Kupfer
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Pennington Choices
Active
(HSG 264, 2012)
and Appx. 3 of HSG 227 (2004))
Executive guides HSG 264 (2012)
Perry Analytical
Active
(HSG 248) – 2021
(PCM) based on HSG 248
Manual based on HSG 248
Perschmann Calibration
Active
Parallelendmaße * 0,5 mm
DIN EN ISO 3650:1999
> 100 mm
Sonderquerschnitt (rund
Parallelendmaße * > 100 mm
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Temperaturmessgrößen
Widerstandsnormal
thermometer (IPRT)
Zeiss Industrielle
Temperaturmessgrößen −35 °C
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Polytest Ingenieure
Active
DIN EN ISO 9934-1
DIN ISO 815-1
DIN ISO 815-2
DIN ISO 4593
DIN EN 50178: 1998
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Poulten Selfe and Lee
Active
TEMPERATURE
Viscosity constant ‘C’
Reference viscometers:
ASTM D4052 (Digital density
Power Diagnostix Systems
Active
Impulsladung
Anstiegszeit
Impulsdauer
Wechselspannung 1 V
> 1,1 kV
+ 3 more
Differentialblutbild
Erythrozyten
Hämatokrit
Leukozyten
Retikulozyten
+ 3 more
External (Tip) Diameter
Helix (lead) total deviation (F
GEARS SPUR/HELICAL EXTERNAL (cont’d)
As for Involute Spline Gauges
HbA1c
Automatisches Blutbild
Leukozyten
Normoblasten
Retikulozyten
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